Add firefox output to Nix package

nix/default.nix

···
 
   src = ./..;
 
+  outputs = [ "out" "firefox" ];
+
   nativeBuildInputs = [
     nodejs_22
     pnpm_10.configHook
···
     runHook preBuild
 
     pnpm run build
+    pnpm run browser-mv2
 
     runHook postBuild
   '';
···
     runHook preInstall
 
     cp -r dist $out
+
+    mkdir -p $firefox/share/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/
+    mv $out/browser-mv2 $firefox/share/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/{0fb6d66f-f22d-4555-a87b-34ef4bea5e2a}
 
     runHook postInstall
   '';

packages/browser/manifestv2.json

···
       "run_at": "document_start",
       "world": "MAIN"
     }
-  ]
+  ],
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "{0fb6d66f-f22d-4555-a87b-34ef4bea5e2a}"
+    }
+  }
 }